JPS63286858A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To reduce dark decay of charged potential and to prevent charging characteristics from being affected by change of an external environmental atmosphere by forming an aluminum substrate having an anodized film prepared by anodic oxidation using a boric acid electrolytic solution and an amorphous silicon photosensitive layer. CONSTITUTION:The anodized film 2 is prepared on the aluminum substrate 1 by cutting and mirror finishing the surface of the aluminum substrate 1, forming it into a desired shape, cleaning it in an organic solvent or a flon type solvent with ultrasonic waves, likewise cleaning it in pure water, immersing in the boric acid electrolytic solution this substrate as the anode and a stainless steel plate or an aluminum plate as a cathode apart from each other by a prescribed distance, and executing the anode oxidation. Then, the amorphous silicon photosensitive layer 3 is formed on the film 2 of the substrate 1 by the vapor deposition method or the like, thus permitting the obtained electrophotographic sensitive body to be small in dark decay, extremely high in chargeability, and not affected on the charging characteristics by change of the external environmental atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor, and particularly to an electrophotographic photoreceptor using amorphous silicon in the photosensitive layer.

Conventional technology Electrophotography is a method in which an electrostatic latent image is formed by charging a photoreceptor and imagewise exposure, and after this latent image is developed with a developer, the toner image is transferred to transfer paper and fixed to obtain a copy. known as. The photoreceptor used in this electrophotographic method basically has a photosensitive layer laminated on a conductive substrate. Conventionally, materials constituting the photosensitive layer include inorganic photosensitive materials such as selenium or selenium alloys, cadmium sulfide, and zinc oxide, or materials such as polyvinylcarbazole, trinitrofluorenone, bisazo pigments, phthalocyanine, pyrazoline, and hydrazone. Organic photosensitive materials are known, and are used with a single photosensitive layer or a stack of photosensitive layers. However, these conventionally used photosensitive layers have poor durability and
There are still problems to be solved in terms of heat resistance, photosensitivity, etc.

In recent years, photoreceptors using amorphous silicon (a-3+) as the photosensitive layer have been known, and various attempts have been made to improve them. This photoreceptor using amorphous silicon is one in which an amorphous silicon film is formed on a conductive substrate using silane (S i H4) gas using a glow discharge decomposition method or the like. It exhibits photoconductivity due to hydrogen atoms incorporated therein. This amorphous silicon photoreceptor has a photosensitive layer that has a high surface hardness, is resistant to scratches, is resistant to abrasion, has high heat resistance, and is excellent in mechanical strength.

Furthermore, amorphous silicon has a wide spectral sensitivity range and has excellent photosensitivity, such as high photosensitivity.

Problems to be Solved by the Invention However, on the other hand, electrophotographic photoreceptors using amorphous silicon have the disadvantage that dark decay is large and a sufficient charging potential cannot be obtained even when charged. That is, when an amorphous silicon photoreceptor is charged, imagewise exposed to form an electrostatic latent image, and then developed, the surface charge on the photoreceptor is exposed to light during the image exposure process or the development process. Even the charge on the parts that are not affected is attenuated, making it impossible to obtain the charging potential necessary for development. If a copy is made using a photoreceptor with such a large dark attenuation of the charged potential, the copy will have a low image density and poor reproducibility of halftones.

As a countermeasure against the decrease in charging potential caused by this large dark decay, a charge injection blocking layer (a p-type a-3i layer for positive charging, an n-type a-3i layer for negative charging) is generally provided at the interface between the photosensitive layer and the conductive substrate. -3i layer). However, in this case, in order to improve charging properties, it is necessary to take measures such as making the charge injection blocking layer relatively thick or increasing the impurity concentration in the charge injection blocking layer. However, there are manufacturing disadvantages such as an increase in the amount of gas used (doping gas) or an increase in the amount of gas used (doping gas).

Additionally, photoreceptors using amorphous silicon have the following drawbacks in terms of photosensitivity. That is, although a photoreceptor using amorphous silicon has high photosensitivity to light with a wavelength of 400 nm to 700 nm, its photosensitivity to longer wavelength light of 700 nm or more is low. Declines rapidly.

Recently, there has been a demand for an electrophotographic photoreceptor that has good photosensitivity to long-wavelength light up to around aoonm as a photoreceptor for laser beam printers using a semiconductor laser as a light source. However, for semiconductor laser printers,
It cannot be put to practical use.

As a countermeasure against this decrease in photosensitivity to long-wavelength light with a wavelength of 700 nm or more, measures such as introducing a layer mainly composed of amorphous silicon-germanium (a-3i:Ge) into the photoreceptor structure are generally taken. is taken. This is Ge
Since the energy bandgap of a-3i is smaller than that of a-3i, the idea is that by adding Ge to a-3i, the energy bandgap is reduced and the photosensitivity on the long wavelength side is increased. However, the a-3ixGe layer generally has a high defect density and a large number of thermally generated carriers due to its small energy bandgap. Therefore, the use of the a-8i:Ge layer has drawbacks such as an increase in the dark decay rate and a decrease in chargeability.

Furthermore, in creating the a-3i:(3e layer, GeH4 (germane), which is one of the raw material gases commonly used, is expensive, so the use of the a-3i:(3e layer is It has the disadvantage of increasing the manufacturing cost of the body.

An object of the present invention is to provide an electrophotographic photoreceptor using amorphous silicon that eliminates the above-mentioned drawbacks of the conventional technology.

An object of the present invention is to provide an electrophotographic photoreceptor that uses amorphous silicon and has extremely small dark decay of the charged potential.

Another object of the present invention is to provide an electrophotographic photoreceptor whose charging characteristics are not affected by changes in the external atmosphere.

Another object of the present invention is to provide an electrophotographic photoreceptor with excellent image quality even after repeated use.

Another object of the present invention is to provide an electrophotographic photoreceptor that has long wavelength sensitivity up to around 800 nm and is applicable as a photoreceptor for semiconductor laser beam printers.

Another object of the present invention is to provide not only the above-mentioned long wavelength range but also 450 wavelength range.
An object of the present invention is to provide an electrophotographic photoreceptor that has enhanced photosensitivity to light in a wide range of wavelengths from the visible light region of around nm to aeonm to the infrared region.

Another object of the present invention is to provide an electrophotographic photoreceptor with excellent adhesion between a substrate and a photosensitive layer.

Still another object of the present invention is to have high heat resistance and chemical stability;
Another object of the present invention is to provide an electrophotographic photoreceptor that has high mechanical strength and excellent wear resistance.

Means for Solving the Problems As a result of intensive studies on anodizing treatment of aluminum substrates used in photoreceptors, the inventor has found that the above object can be achieved without substantially modifying the photosensitive layer. They discovered this and completed the present invention.

That is, the above object of the present invention is to provide an electrophotographic photosensitive material comprising an aluminum substrate having an anodic oxide film formed by anodic oxidation using a boric acid electrolyte solution and an amorphous silicon photosensitive layer. This can be achieved by providing the body.

The object of the present invention can be achieved more effectively when the boric acid electrolyte solution contains boric acid and borax.

The present invention will be explained in detail below.

An example of the most basic structure of the electrophotographic photoreceptor of the present invention is shown in FIG. 1 of the accompanying drawings. In FIG. 1, 1 is an aluminum substrate, 2 is an anodized film, and 3 is an amorphous silicon photosensitive layer.

In the present invention, as the aluminum substrate 1 for obtaining an anodic oxide film with good characteristics, in addition to pure A1-based materials, AI-MO-based, AI-MO-3i-based, and AI-MO
-Mn series, Al-Mn series, Al-Cu-Mg series, Al-
Cu-N1 series, A1-CU series, A I-3i series, A
l-Cu series, AI-CLI-Zn series, Al-Cu-Ni
system, AI-3i system, Al-Cu-8, system, Al-
Examples include substrates formed by appropriately selecting aluminum alloy materials such as Mg-3i-based materials.

In the present invention, anodizing treatment for forming the anodic oxide film 2 on the aluminum substrate 1 is performed as follows. An aluminum substrate whose surface has been mirror-cut and processed into a desired shape is ultrasonically cleaned in an organic solvent or a fluorocarbon solvent. Subsequently, ultrasonic cleaning is performed in pure water to clean the surface of the aluminum substrate, for example, if the aluminum substrate has a cylindrical shape, the inner and outer surfaces of the cylinder. If this cleaning treatment is insufficient, a high-quality anodic oxide film that satisfies the desired characteristics cannot be formed. After this cleaning treatment, the aluminum substrate may be subjected to pretreatment such as boiling treatment in boiling pure water or heated steam treatment, if necessary.

Subsequently, an anodic oxide film is formed on the aluminum substrate. Electrolyte solution (anodizing solution) is placed in an electrolytic tank (anodizing tank) made of stainless steel or hard glass.
Fill to the specified level.

The present invention is characterized in that a boric acid electrolyte solution is used as the electrolyte solution. By using a boric acid electrolyte solution, a highly insulating barrier type film with almost no porous areas can be obtained.

This boric acid electrolyte solution is usually prepared using boric acid (H2
A solution containing 0.5 to 60% by weight of SO4) is used. More preferably, a solution of 5 to 20% by weight dissolved in pure water is used. In particular, the above 5 to 20% by weight I! It is preferable to set the temperature at a certain temperature because a high-quality anodic oxide film is most stably formed. Moreover, in this case, the amount of electricity consumed during anodization can also be reduced. The pure water used here can be distilled water or ion-exchanged water, but it is especially important that impurities such as chlorine valves are sufficiently removed to prevent corrosion of the anodic oxide film and pinhole formation. is necessary.

For the boric acid electrolyte solution, only boric acid may be added to pure water, but borax (sodium tetraborate, N82 B407-
It is preferable to add 10820> at the same time, since this makes it easier to control the electrical conductivity of the electrolyte solution. The content of borax is 0 to 30% by weight, more preferably 0.1 to 15% by weight, based on pure water.

Next, an anode (Anode) is placed in this boric acid electrolyte solution.
) An aluminum substrate for an electrophotographic photoreceptor is used as a cathode, and a stainless steel plate or an aluminum plate is used as a cathode. The distance between the electrodes at this time is appropriately set between 1 cm and 100 cm. A DC power supply device is prepared, its positive terminal is connected to the aluminum substrate, its negative terminal is connected to the cathode plate, and electricity is applied between the anode and cathode electrodes in the electrolyte solution. This energization forms an anodic oxide film on the anode aluminum substrate. An example of the relationship between current and voltage during anodization using a boric acid electrolyte solution is shown in FIG. 2 of the accompanying drawings. When the voltage is increased under constant current in region A in FIG. 2, a film having a thickness corresponding to the voltage is formed. (10-14 people/V
). Then, when holding a constant voltage in region B, the current decreases with time.

By combining regions A and B, a barrier type insulating anodic oxide film having the final thickness is formed.

The current density (@ area A) during anodization is usually 0,000
1-10A/crA, preferably 0.0005-
IA/cn. Further, the anodic oxidation voltage (region B) is usually 0 to 1000V, preferably 0 to 700V. Further, the temperature of the electrolyte solution is 40 to 100°C, preferably 70°C.
The temperature is set at ~95°C. The anodizing time is the time required to obtain the required film thickness and the desired insulation properties of the film, i.e. the required current reduction value (leakage current) in region B of Figure 2 of the attached drawings. It is determined as appropriate depending on the time required to obtain.

The anodic oxide film formed by the anodizing method using a boric acid electrolyte solution is generally known as an alumite film, etc. Porosity (density of pores) compared to
is extremely low or almost zero. This point is also considered to be an effective factor of the present invention. If necessary, a sealing treatment may be performed. By the above procedure, an anodic oxide film 2 is formed on the aluminum substrate 1 shown in FIG. 1 of the accompanying drawings. The anodic oxide film thus formed on the aluminum substrate is washed with pure water as necessary, and then dried.

The thickness of the anodic oxide film is 0.001 to 20 μm, preferably 0.005 to 2 μm.

Next, amorphous silicon (a-3
i: amorphous silicon) The photosensitive layer 3 will be explained. The amorphous silicon photosensitive layer 3 is preferably composed of silicon as a main component. Such an amorphous silicon photosensitive layer mainly composed of silicon can be formed on an aluminum substrate by a glow discharge method, a sputtering method, an ion blasting method, a vacuum evaporation method, or the like. These film forming methods are appropriately selected depending on the purpose, but silane (S) is
f H4) A method of decomposing gas by glow discharge (glow discharge method) is preferable. According to this method, a film containing an appropriate amount of hydrogen, which has a relatively high dark resistance and high photosensitivity, such as electrophotography, is preferable. An amorphous silicon photosensitive layer having properties suitable for use as a photoreceptor can be obtained. Below, plasma CVD
Let me explain using the law as an example.

Examples of raw materials for producing an amorphous silicon photosensitive layer containing silicon as a main component include silanes such as silane and disilane. Furthermore, when forming the amorphous silicon photosensitive layer, it is also possible to use various mixed gases, for example, carrier gases such as hydrogen, helium, argon, and neon, as required. In addition, diborane (
B2H6) gas, addition of impurity elements such as boron (B) or phosphorus (P) into the photoconductive layer film by mixing dopant gas such as phosphine (PH3) gas (doping)
You can also do Further, for the purpose of increasing dark resistance, increasing photosensitivity, or increasing charging ability (charging ability or charging potential per unit film thickness of light), halogen atoms, carbon atoms, and oxygen may be added to the photosensitive layer. It may contain atoms, nitrogen atoms, etc. Furthermore, it is also possible to add an element such as germanium (Ge) to the photosensitive layer for the purpose of increasing the sensitivity in the long wavelength region. In particular, the photosensitive layer is preferably an i-type semiconductor layer containing silicon as a main component and adding a small amount of a Group I element of the periodic table of elements (preferably boron). In order to add and contain the above-mentioned various elements in the photosensitive layer, glow discharge decomposition may be performed by introducing a gasified substance containing these elements together with silane gas as the main raw material into a plasma CVD apparatus.

The film thickness of the photosensitive layer containing silicon as a main component can be set arbitrarily, but is 1μTrL to 100μ, particularly 5μTrL to 5μTrL.
It is desirable to set it within a range of 50 μm.

Further, in the electrophotographic photoreceptor of the present invention, another layer may be formed adjacent to the top or bottom of the amorphous silicon photosensitive layer containing silicon as a main component, if necessary. These layers include, for example, the following:

As a charge injection blocking layer, for example, an n layer made of amorphous silicon doped with an element from group Ⅰ or group V of the periodic table of elements.
A type semiconductor layer, an n-type semiconductor layer, or an insulating layer, a long-wavelength sensitizing auxiliary layer, such as a layer made of amorphous silicon with germanium or tin added, and an adhesive layer made of amorphous silicon with nitrogen, nitrogen, etc. Layers that can control the electrical and image characteristics of the photoreceptor, such as layers to which carbon, oxygen, etc. are added, and layers that simultaneously contain elements of Group IB and Group V of the Periodic Table of Elements, etc., can be used. The film thickness of each of these layers can be arbitrarily determined, but is usually 0.01 μTrL to 10
It is used by setting it within the range of μ employment.

In the present invention, when a p-type amorphous silicon layer is provided between the amorphous silicon photosensitive layer and the anodic oxide film formed on the aluminum substrate, the charging characteristics and photosensitivity are most significantly improved. It is something that

The above-mentioned amorphous silicon photosensitive layer and other layers can be formed by a plasma CVD method, but the amorphous silicon photosensitive layer to which the above-mentioned impurity element is added can be formed using a gasified substance containing the above-mentioned impurity element. Plasma CV with silane gas
It is formed by introducing it into D apparatus and performing glow discharge decomposition.

Silane (S i 1-14
>Gas is decomposed by glow discharge. In the film formation of the amorphous silicon photosensitive layer containing silicon as the main component and each layer provided adjacent to the upper and lower parts thereof, both AC discharge and DC discharge can be employed as an effective film forming means. However, taking the case of AC discharge as an example, it is as follows. That is, the frequency is usually o, i~30) IH
z, preferably 5 to 20 HIIz, the degree of vacuum during discharge is 0
．． 1-5 Torr (13, 3-6B, 7Pa),
The heating temperature of the substrate is 100 to 400°C.

Example Next, the present invention will be explained in detail by way of examples.

Example 1 A cylindrical high-purity (4N) At-Mg alloy substrate (hereinafter referred to as All plate) with a mirror-cut surface and an outer diameter of 121 mφ was ultrasonically cleaned using acetone at room temperature for 10 minutes, and then Then, ultrasonic cleaning was performed in pure water at room temperature for 10 minutes. For this substrate, add 110% by weight of HO in pure water.
Anodizing treatment was performed using a solution containing 1% by weight of borax. The anodizing conditions at that time were a liquid temperature of 85°C,
The current density was 2 mA/d and the anodization time was 40 minutes.

The treated A1 substrate was removed from the anodizing solution, ultrasonically cleaned in pure water for 10 minutes, and then dried. The thickness of the anodic oxide film on the A1 substrate thus obtained was about 0.15 μm. Next, the AI substrate on which the anodic oxide film was formed was placed at a predetermined position in a capacitively coupled plasma CVD apparatus capable of forming an amorphous silicon film on a cylindrical substrate. Subsequently, silane (S i
H4) By glow discharge decomposition of a mixed gas of gas and diborane (82H6) gas, a so-called i-type film containing hydrogen and a trace amount of boron with a relatively high dark resistance is formed on the A1 substrate on which the above anodic oxide film is formed. An amorphous silicon film was produced.

The conditions for forming the amorphous silicon film at this time were as follows.

A cylindrical shape A is placed at a predetermined position within the reaction chamber of the plasma CVD equipment.
1 board is installed, and the board temperature is set to 250°C, which is the predetermined temperature.
100% silane (S + H4) during the reaction
1100 pp diborane (82 to 16) gas diluted with 1 hydrogen at 2.5 CC per minute, and ioo
% hydrogen (H2) gas was introduced at a rate of 200 CC per minute, and the internal pressure of the reactor was maintained at 1.5 Torr (200, ON/m>).The high frequency power of IZ was applied, and a glow discharge was caused. , and the output of the high frequency power supply is 300
I kept it at W. A with an anodic oxide film provided in this way
A photoreceptor was obtained having a so-called i-type amorphous silicon photosensitive layer having a high dark resistance and containing hydrogen and a very small amount of boron and having a thickness of 20 μm on an I substrate.

When the positive charging characteristics of the obtained electrophotographic photoreceptor were measured, the contrast potential (charged potential - residual potential) was 600 V when the photoreceptor inflow current was 10 μA / cm.
, and the dark decay rate was 35%/Sec.

Subsequently, the wavelength is 450. When the photosensitivity during positive charging at each wavelength was measured using monochromatic light of 650 and 800 nm, the incident light intensity was 10 erg・5 ec-'
- cm', the half-decrease exposure amount was 25.3.2 and 14.5 erg·cm', respectively, in the order of the wavelengths mentioned above.

For comparison, on a substrate that has not been anodized,
A photoreceptor having an i-type amorphous silicon photosensitive layer was prepared by the same method and under the same conditions as above.

When the positive charging characteristics of this electrophotographic photoreceptor were measured using a similar method, the contrast potential (charging potential - residual potential) was 300 V when the photoreceptor inflow current was 10 μA/α.
, and the dark decay rate was 68%/Sec. Subsequently, the wavelength is 450. When the photosensitivity during positive charging at each wavelength was measured using monochromatic light of 650 and 800 nm, the incident light intensity was 10 erg・5ec−1・cIIt
-2, the half-decrease exposure doses were 35.4.0 and 25 erg-Cm-2, respectively, in the order of the wavelengths mentioned above. Example 2 A cylindrical high-purity (4N>AI-Mq alloy substrate with an outer diameter of 121 mφ and a mirror-cut surface was ultrasonically cleaned at room temperature using acetone for 10 minutes, and then washed in pure water at room temperature. Ultrasonic cleaning was performed for 10 minutes.

Subsequently, boiling treatment in pure boiling water was performed for 10 minutes. This substrate was anodized using a solution prepared by adding 110i% by weight of boron and 1% by weight of boron in pure water. The anodizing conditions at that time were a liquid temperature of 85° C., a current density of 3 mA/Cri, and an anodizing treatment for 45 minutes.

The treated A1 substrate was removed from the anodizing solution, ultrasonically cleaned in pure water for 10 minutes, and then dried. The thickness of the anodic oxide film on the AI substrate thus obtained was about 0.3 μm. Next, the A1 substrate on which the anodic oxide film was formed was placed at a predetermined position in a capacitively coupled plasma CVD apparatus capable of forming an amorphous silicon film on a cylindrical substrate. Subsequently, silane (S i H
4) By glow discharge decomposition of a mixed gas of gas and diborane (B2 to 16) gas, a so-called p-type amorphous silicon film containing hydrogen and boron is formed on the A1 substrate on which the above anodic oxide film has been formed. The amorphous silicon film was formed under the following conditions.

A cylindrical shape A is placed at a predetermined position within the reaction chamber of the plasma CVD equipment.
Install the I board and keep the board temperature at the specified temperature of 250°C.
100% silane (S i H4) was added during the reaction.
Gas was introduced at 200 cc per minute, and 1100 pp diborane (82H6) gas diluted with hydrogen was introduced at 200 cc per minute, and after maintaining the internal pressure in the reaction tank at 0.5 Torr (66,7 N/rd), a high frequency power of 13.568 H2 was applied. was applied to generate a glow discharge, and the output of the high frequency power source was maintained at 100 W. In this way, Yang! ! ! A so-called p-type amorphous silicon layer containing hydrogen and boron and having a thickness of 0.5 μm was formed on an AI substrate provided with an oxide film.

Next, silane (S i 84) gas and diborane (B, 2
H6) By glow discharge decomposition of a gas mixture, a so-called i-type amorphous silicon film containing hydrogen and a trace amount of boron and having a relatively high dark resistance is formed on the above p-type amorphous silicon layer. generated. The conditions for forming the amorphous silicon film at this time were as follows.

A cylindrical A1 substrate is installed at a predetermined position in the reaction chamber of a plasma CVD apparatus, and the substrate temperature is set at a predetermined temperature of 250 ℃.
℃ and 100% silane (S + H4
) gas at 250 CC per minute, hydrogen diluted ioppm diborane (B2H6) gas,! -3 CC1 changes per minute, 100%
Hydrogen gas was introduced at a rate of 250 cc per minute to maintain an internal pressure of 1.5 Torr (200, ON/rd) in the reaction tank, and then high-frequency power of 13°568H7 was applied to generate glow discharge. , the output of the high frequency power supply is 3
The power was maintained at 50W. In this way, a so-called i-type amorphous silicon photosensitive layer having a thickness of 20 μm and containing hydrogen and a very small amount of boron and having a high dark resistance was obtained.

By the above procedure, p
A photoreceptor having an i-type amorphous silicon layer and an i-type amorphous silicon photosensitive layer was produced.

When the positive charging characteristics of the obtained electrophotographic photoreceptor were measured, the contrast potential (charged potential - residual potential) was 750 when the photoreceptor inflow current was 10 μA/cm.
V, and the dark decay rate was 25%/Sec.

Subsequently, wavelength 450. When the photosensitivity during positive charging at each wavelength was measured using monochromatic light of 650 and 800 nm, the incident light intensity was 1oerg-5ec-1・c
In the case of IIt-2, the "half-exposure" is 23.3.0 and 11.50 rg.ff-2 teats, respectively, in the order of the above wavelengths.

For comparison, a photoreceptor having a p-type amorphous silicon layer and an i-type amorphous silicon photosensitive layer was fabricated on an Al plate that had not been anodized using the same method and under the same conditions as above. . When the positive charging characteristics of this electrophotographic photoreceptor were measured using the same method, the photoreceptor inflow current was 10 μA.
/ cm, the contrast potential (charged potential - residual potential) was 400 V, and the dark decay rate was 55%/SeC. Subsequently, the wavelength is 450. 650 and 800nm
When the photosensitivity during positive charging at each wavelength was measured using monochromatic light, the incident light intensity was 10 erg -sec'
・cm-2 (in case of D, the half-decrease exposure amount is 33.3.7 and 22erCl -Cm''' in the order of the wavelengths above, respectively)
I failed at 2.

Example 3 A cylindrical high-purity (4N>A I-fVtg alloy substrate with an outer diameter of 121#φ and a mirror-cut surface was ultrasonically cleaned at air temperature for 10 minutes using acetone, and then,
Ultrasonic cleaning was performed for 10 minutes in air-temperature pure water.

Subsequently, a boiling treatment in pure boiling water was performed for 10 minutes.

This substrate was anodized using a solution containing 10% by weight of boric acid and 1% by weight of boron in pure water. The anodizing conditions at that time were a liquid temperature of 85° C., a current density of 2.5 mA/7, and an anodizing time of 45 minutes.

The treated A1 substrate was removed from the anodizing solution, ultrasonically cleaned in pure water for 10 minutes, and then dried. The thickness of the anodic oxide film on the AI substrate thus obtained was about 0.2 μm. Next, the A1 substrate on which the anodic oxide film was formed was placed at a predetermined position in a capacitively coupled plasma CVD apparatus capable of forming an amorphous silicon film on a cylindrical substrate. Subsequently, silane (S i 1
-14 > By glow discharge decomposition of a mixed gas of gas and diborane (82H6) gas, a so-called i-type film containing hydrogen and a trace amount of boron with a relatively high dark resistance is formed on the Al plate on which the above anodic oxide film is formed. produced an amorphous silicon film. The conditions for forming the amorphous silicon film at this time were as follows.

Cylindrical type A is placed at a predetermined position inside the reaction chamber of the plasma CVD equipment.
Install the I board and set the board temperature to the specified temperature of 250°C.
100% silane (S i H4) in the reaction chamber.
Gas was introduced at 400 cc per minute, 1100 pp diborane (B2H6) gas diluted with hydrogen was introduced at 4 cc/min, and 100% hydrogen (machi) gas was introduced at 400 cc/min.
．． After maintaining the internal pressure at 5 Torr (200, ON/TIt>), a high frequency power of 13.568 H2 was applied to generate a glow discharge, and the output of the high frequency power supply was maintained at 350 W. In this way, the anodic oxide film was A: A photoreceptor was obtained having a so-called i-type amorphous silicon photosensitive layer with a high dark resistance and containing hydrogen and a very small amount of boron and having a thickness of 25 μm on a substrate.

When the positive charging characteristics of the obtained electrophotographic photoreceptor were measured, the contrast potential (charged potential - residual potential) was 680 V when the photoreceptor inflow current was 10 μA / cm.
First, the dark decay rate was 37%/SeG.

Subsequently, when the photosensitivity during positive charging at each wavelength was measured using monochromatic light with a wavelength of 450.650 and aoonm, the incident light intensity was 1 oerg-5ec-1 cm.
', the half-decreased exposure amount is it, - in the order of wavelengths above.
F25.5.3.2 and Cf 14.7erQ-cm-
``There was a time.

Furthermore, the adhesion between the A1 substrate and the amorphous silicon photosensitive layer was good.

For comparison, a photoreceptor having an i-type amorphous silicon photosensitive layer was fabricated on an AI substrate that had not been anodized by the same method and under the same conditions as above. When the positive charging characteristics of this electrophotographic photoreceptor were measured in a similar manner, when the photoreceptor inflow current was 10 μA/cm, the contrast potential (charged potential - residual potential) was 340 V, and the dark decay rate was 72. %/sec. Subsequently, wavelength 450
．． When the photosensitivity during positive charging at each wavelength was measured using monochromatic light of 650 and 800 nm, it was found that the incident light intensity was 10 erg -5ec-'-H-'' (in case of D,
half Wc it light m c, 3 each in the order of the above wavelengths
6.4.1 and 278rg・CI! It was t-2. Further, peeling from the A1 substrate was observed in a part of the amorphous silicon photosensitive layer.

Example 4 External diameter: 121 mm with mirror-cut surface. A high purity (4N>Al-Mg alloy substrate) having a cylindrical shape of φ was ultrasonically cleaned using acetone at room temperature for 10 minutes, and then ultrasonically cleaned in pure water at room temperature for 10 minutes.

Subsequently, boiling treatment in pure boiling water was performed for 10 minutes.

This substrate was anodized using a solution containing 10% by weight of boric acid and 1.5% by weight of borax in pure water. The anodic oxidation conditions were a liquid temperature of 85° C., a current density of 3 mA/cm, and an anodization time of 45 minutes.

The treated A1 substrate was removed from the anodizing solution, ultrasonically cleaned in pure water for 10 minutes, and then dried. The thickness of the anodic oxide film on the AI substrate thus obtained was about 0.25 μm. Next, the A1 substrate on which the anodic oxide film was formed was placed at a predetermined position in a capacitively coupled plasma CVD apparatus capable of forming an amorphous silicon film on a cylindrical substrate. Subsequently, silane (SiH4
) gas and diborane (B2H6) gas by glow discharge decomposition, a so-called p-type amorphous silicon film containing hydrogen and boron was generated on the AI substrate on which the above anodic oxide film was formed. . The conditions for forming the amorphous silicon film at this time were as follows.

Cylindrical A is placed at a predetermined position in the reaction chamber of the plasma CVD device.
1 board is installed, and the board temperature is set to 250°C, which is the predetermined temperature.
100% silane (SiH4) gas was introduced into the reaction chamber at a rate of 200 cc per minute, hydrogen-diluted 11001)p diborane (B2 H5) gas was introduced at a rate of 200 cc/min, and the inside of the reaction chamber was maintained at 0.5 Torr (66, 7N/Tri>
After maintaining the internal pressure at , 13.56 MHz high frequency power was applied to generate glow discharge, and the output of the high frequency power source was maintained at 120 W. In this way, a so-called p-type amorphous silicon layer containing hydrogen and boron and having a thickness of 0.5 μm was formed on the A1 substrate provided with the anodic oxide film.

Next, silane (S i H4) gas and diborane (82
H6) By glow discharge decomposition of a gas mixture, a so-called i-type amorphous silicon film containing hydrogen and a trace amount of boron and having a relatively high dark resistance is formed on the above p-type amorphous silicon layer. was generated. The conditions for forming the amorphous silicon film at this time were as follows.

Cylindrical type A is placed at a predetermined position inside the reaction chamber of the plasma CVD equipment.
1 board is installed, and the board temperature is set to 250°C, which is the predetermined temperature.
In the reaction chamber, 100% silane (SiH4) gas was supplied at 220cc/min, hydrogen diluted (7) 100ppm diborane (82H6) gas was supplied at 2.5cc/min, and ioo% hydrogen (H2) gas was supplied at 200cc/min. After maintaining the internal pressure in the reaction tank at 1.5 Torr (200, ON/Td>), high-frequency power of 13.568 H2 was applied to generate a glow discharge, and the output of the high-frequency power source was maintained at 300 W. In this way, a so-called i-type amorphous silicon photosensitive layer having a thickness of 25 μm and containing hydrogen and a very small amount of boron and having a high dark resistance was obtained.

By the above procedure, p
A photoreceptor having an i-type amorphous silicon layer and an i-type amorphous silicon photosensitive layer was produced.

When the positive charging characteristics of the obtained electrophotographic photoreceptor were measured, the contrast potential (charged potential - residual potential) was 810 V when the photoreceptor inflow current was 10 μA / cm.
First, the dark decay rate was 27%/SeC.

Subsequently, wavelength 450. When the photosensitivity during positive charging at each wavelength was measured using monochromatic light of 650 nm and 10 nm, the incident light intensity was 10 erg・5ec−1・
cm', the half-decay exposure was set at 24.3.0 and 11.6 erg*cm-2, respectively, in the order of the wavelengths mentioned above. Furthermore, the adhesion between the AI substrate and the amorphous silicon layer was good.

For comparison, a photoreceptor having a p-type amorphous silicon layer and an i-type amorphous silicon photosensitive layer was fabricated on an A1 substrate that had not been anodized using the same method and conditions as above. . When the positive charging characteristics of this electrophotographic photoreceptor were measured using the same method, the photoreceptor inflow current was 10 μA.
/ cm, the contrast potential (charged potential - residual potential) was 430 V, and the dark decay rate was 60%/sec. Subsequently, the wavelength is 450. 650 and 800n
The photosensitivity during positive charging at each wavelength was measured using monochromatic light of m, and the incident light intensity was 10erl; l -5
In the case of ec-1" Cm-2, the half-decrease exposure doses were 34.4 and 25 erg cm', respectively, in the order of the wavelengths mentioned above. In addition, part of the amorphous silicon layer was peeled off from the AIDS plate. It was seen.

Effects of the Invention As is clear from the above results, the electrophotographic photoreceptor having an amorphous silicon photosensitive layer of the present invention has an anodic oxide film formed by anodic oxidation using a boric acid electrolyte solution. Since it is constructed using an aluminum substrate, it has low dark decay and extremely high charging properties, and its charging characteristics are not affected by changes in the external environment. It has increased photosensitivity to light. It is particularly effective in improving photosensitivity in the long wavelength region around 800 nm.
It can be applied as a photoreceptor for semiconductor laser beam printers.

Further, the electrophotographic photoreceptor of the present invention has excellent adhesion between the A1 substrate and the amorphous silicon photosensitive layer.

Furthermore, the electrophotographic photoreceptor of the present invention has high heat resistance, high chemical stability, high mechanical strength, and excellent abrasion resistance.
Provides images of excellent quality even after repeated use.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the basic structure of the electrophotographic photoreceptor of the present invention, and FIG. 2 is a graph showing the relationship between current and voltage during anodic oxidation. 1... Aluminum substrate, 2... Anodic oxide film, 3
...Amorphous silicon photosensitive layer. Patent applicant Fuji Xerox Co., Ltd. Agent
Patent attorney Tsuyoshi Watanabe Figure 1 Time t1t2 Figure 2 Procedural amendment (voluntary) March 31, 1985 Commissioner of the Patent Office Kunio Ogawa Membrane Office 3-3-5 Akasaka, Minato-ku, Tokyo @ Name (
549) Fuji Xerox Co., Ltd. Representative Yota Kobayashi Department 6 Contents of the amendment 0) Changed "problem to be solved by the invention" in the first line of page 4 of the specification to "problem to be solved by the invention" to correct. ■ "r-Cu system, A1+1-si system... Al-Mg-8t system, etc." on page 9, lines 6 to 8,
u series, A1-5i series, Al-Cu-Zn series, Al-8i
system, Al-Cu-3i system, etc.". ■ Add “Example 2” in the first line of page 21 of the same page to the first line of the same page.
Insert between the line and the second line. that's all

Claims (5)

[Claims] (1) An electrophotographic photoreceptor comprising an aluminum substrate having an anodic oxide film formed by anodic oxidation using a boric acid electrolyte solution and an amorphous silicon photosensitive layer. (2) The electrophotographic photoreceptor according to claim 1, wherein the boric acid electrolyte solution contains boric acid and borax in pure water. (3) The content of boric acid in pure water is 0.5 to 60% by weight,
The electrophotographic photoreceptor according to claim 1 or 2, wherein the content of borax is 0 to 30% by weight. (4) The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer is made of an i-type amorphous silicon layer. (5) A photosensitive material for electrophotography according to claim 1, characterized in that a p-type amorphous silicon layer is provided between the photosensitive layer and the anodic oxide film formed on the aluminum substrate. body.